From the U.S. Pat. No. 3,505,878 a device for skiers for measuring the speed and/or the distance skied, consisting of two toothed wheels on a common shaft positioned laterally to the ski, the toothing of the wheels being in mechanical contact with the snow, means for indicating the speed and/or the distance skied and means for transmitting the rotation of the wheels to the indicating means, is known. In this device there is no lateral protection for the wheels.